Circularly polarized dielectric antenna

ABSTRACT

An antenna for radiating an electromagnetic field includes a ground plane, a feeding probe, and a dielectric layer. The dielectric layer is disposed on the ground plane and has a radiating surface. The feeding probe electrically is embedded in the dielectric layer, and the feeding probe excites the dielectric layer such that the electromagnetic field radiates from the radiating surface and achieves circular polarization radiation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention generally relates to an antenna for receivingand/or transmitting a circularly polarized radio frequency (RF) signal.

2. Description of the Related Art

Various antennas for receiving circularly polarized RF signals are knownin the art. In the antennas of the prior art, dielectric layers aretypically used to isolate a radiation element, such as a discretemetal-based patch radiation element, from other elements of the antenna,such as a feeding probe and a ground plane. One example of such anantenna is disclosed in United States Patent Application Publication No.2005/0195114 A1 to Yegin et al. (the Yegin et al. publication). TheYegin et al. publication discloses an antenna mounted to a windshield ofan automobile. The antenna includes the ground plane supporting thedielectric layer. Further, the dielectric layer is supporting a metallayer having a slot, and the feeding probe excites the metal layer toradiate across the edges of the dielectric layer.

Although the antenna of the Yegin et al. publication can receive and/ortransmit circularly polarized RF signals, there remains an opportunityto provide an antenna that achieves circular polarization radiationand/or linear polarization radiation from all surfaces of the dielectriclayer that extend transverse relative to the ground plane or areparallel to and spaced from the ground plane and maintain or improve theperformance of the antenna, including increasing bandwidth, increasingefficiency, decreasing size, decreasing manufacturing complexity,decreasing sensitivity, and eliminating surface wave radiation.

SUMMARY OF THE INVENTION AND ADVANTAGES

The invention provides an antenna for radiating an electromagneticfield. The antenna includes a ground plane and a dielectric layerdisposed on the ground plane and having a radiating surface opposite theground plane. The antenna further includes a feeding probe embedded inthe dielectric layer for electrically exciting the dielectric layer suchthat the electromagnetic field radiates from the radiating surface andachieves circular polarization radiation.

Exciting the dielectric layer with the feeding probe generates theelectromagnetic field to achieve circular polarization radiation in theradiating surface and eliminates the need for a discrete metal-basedpatch radiation element. That is, the antenna of the subject inventioncan operate independent of the metal-based patch radiation elementdisposed within the antenna. Accordingly, the antenna of the subjectinvention results in better gain performance at 20 to 30 degreeelevation angles, as well as other performance characteristics such asincreased bandwidth, increased efficiency, decreased size, decreasedmanufacturing complexity, decreased sensitivity, and minimized surfacewave radiation.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated,as the same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a perspective view of a vehicle with an antenna supported by apane of glass of the vehicle;

FIG. 2A is a perspective view of the preferred embodiment of the antennahaving a dielectric layer disposed on a ground plane;

FIG. 2B is a partial cross-sectional perspective view of the antennahaving a feeding probe embedded in the dielectric layer;

FIG. 3A is a top view of a dielectric layer of the antenna having acircular shape with a pair of perturbation features embodied as notcheshaving triangular shapes;

FIG. 3B is a top view of the dielectric layer of the antenna having acircular shape with a pair of perturbation features embodied as tabshaving triangular shapes;

FIG. 3C is a top view of the dielectric layer of the antenna having acircular shape with a pair of perturbation features embodied as notcheshaving rectangular shapes;

FIG. 3D is a top view of the dielectric layer of the antenna having acircular shape with a pair of perturbation features embodied as tabshaving rectangular shapes;

FIG. 3E is a top view of the dielectric layer of the antenna having arectangular shape with a pair of perturbation features embodied astruncations of opposing corners of the dielectric layer;

FIG. 3F is a top view of the dielectric layer of the antenna having arectangular shape with a pair of perturbation features embodied asnotches having a rectangular shape with sides generally parallel to thesides of the dielectric layer;

FIG. 3G is a top view of the dielectric layer of the antenna having arectangular shape with a pair of perturbation features embodied asnotches having rectangular shapes with sides generally non-parallel tothe sides of the dielectric layer;

FIG. 3H is a top view of the dielectric layer of the antenna having arectangular shape with a pair of perturbation features embodied as tabshaving rectangular shapes;

FIG. 3I is a top view of the dielectric layer of the antenna having acircular shape with a pair of perturbation features embodied as voidshaving triangular shapes;

FIG. 3J is a top view of the dielectric layer of the antenna having acircular shape with a pair of perturbation features embodied as voidshaving rectangular shapes;

FIG. 3K is a top view of the dielectric layer of the antenna having arectangular shape with a pair of perturbation features embodied as voidshaving rectangular shapes;

FIG. 3L is a top view of the dielectric layer of the antenna having arectangular shape with a perturbation feature embodied as a void havinga rectangular shape;

FIG. 4 is a partial cross-sectional side view of the antenna;

FIG. 5 is a perspective view of the antenna having a passive elementdisposed on a vertical surface of the dielectric layer;

FIG. 6 is a chart illustrating the magnitude of the S₁₁ parameter of thepreferred embodiment of the antenna;

FIG. 7 is a chart illustrating input impedance of the preferredembodiment of the antenna;

FIG. 8 is a chart illustrating an axial ratio of the preferredembodiment of the antenna;

FIG. 9 is a chart illustrating radiation gains produced by the preferredembodiment of the antenna;

FIG. 10 is a chart illustrating total gain, right hand circularpolarization gain, and left hand circular polarization gain produced inan XZ-plane by the preferred embodiment of the antenna;

FIG. 11 is a chart illustrating total gain, right hand circularpolarization gain, and left hand circular polarization gain produced ina YZ-plane by the preferred embodiment of the antenna;

FIG. 12 is a chart illustrating the axial ratio of the preferredembodiment of the antenna in the XZ-plane and the YZ-plane; and

FIG. 13 is a partial cross-sectional side view of one embodiment of theantenna showing a protrusion of the pane of glass providing thedielectric layer.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the Figures, wherein like numerals indicate correspondingparts throughout the several views, an antenna for radiating anelectromagnetic field is shown generally at reference numeral 20. In theillustrated embodiments, the antenna 20 is utilized to receive acircularly polarized radio frequency (RF) signal from a satellite. Thoseskilled in the art realize that the antenna 20 may also be used totransmit the circularly polarized RF signal. Specifically, the antenna20 receives a left-hand circularly polarized (LHCP) RF signal like thoseproduced by a Satellite Digital Audio Radio Service (SDARS) provider,such as XM® Satellite Radio or SIRIUS® Satellite Radio. However, it isto be understood that the antenna 20 may also receive a right-handcircularly polarized (RHCP) RF signal.

Referring to FIG. 1, the antenna 20 is preferably integrated with awindow 22 of a vehicle 24. The window 22 may be a rear window(backlite), a front window (windshield), or any other window of thevehicle 24. The antenna 20 may also be implemented in other situationscompletely separate from the vehicle 24, such as on a building orintegrated with a radio receiver. Additionally, the antenna 20 may bedisposed on other locations of the vehicle 24, such as on a side mirror.

Multiple antennas 20 may be implemented as part of a diversity system ofantennas. For instance, the vehicle 24 of the preferred embodiment mayinclude a first antenna 20 on the windshield and a second antenna 20 onthe backlite. These antennas 20 would both be electrically connected toa receiver (not shown) within the vehicle 24. Those skilled in the artrealize several processing techniques may be used to achieve diversityreception. In one such technique, a switch (not shown) may beimplemented to select the antenna 20 that is currently receiving astronger RF signal from the satellite.

The preferred window 22 includes at least one nonconductive pane 26. Theterm “nonconductive” refers to a material, such as an insulator ordielectric, that when placed between conductors at different potentials,permits only a small or negligible current in phase with the appliedvoltage to flow through material. Typically, nonconductive materialshave conductivities on the order of nanosiemens/meter.

In the illustrated embodiments, the nonconductive pane 26 is implementedas at least one pane of glass. Of course, the window 22 may include morethan one pane of glass. Those skilled in the art realize that automotivewindows 22, particularly windshields, may include two panes of glasssandwiching an adhesive interlayer. The adhesive interlayer may be alayer of polyvinyl butyral (PVB). Of course, other adhesive interlayerswould also be acceptable. The nonconductive pane 26 is preferablyautomotive glass and more preferably soda-lime-silica glass. The pane ofglass defines a thickness between 1.5 and 5.0 mm, preferably 3.1 mm. Thepane of glass also has a relative permittivity between 5 and 9,preferably 7. Those skilled in the art, however, realize that thenonconductive pane 26 may be formed from plastic, fiberglass, or othersuitable nonconductive materials. Furthermore, the nonconductive pane 26functions as a radome for the antenna 20. That is, the nonconductivepane 26 protects the other components of the antenna 20 from moisture,wind, dust, etc. that are present outside the vehicle 24.

Referring now to FIGS. 2A-B and 4, the antenna 20 includes a groundplane 28 for reflecting energy in a direction parallel to a verticalaxis 44. The ground plane 28 is typically spaced from and disposedsubstantially parallel to the nonconductive pane 26. The ground plane 28is formed of a generally flat electrically conductive material, such asa conductive metal like copper or aluminum. The ground plane 28generally defines a rectangular shape, specifically a square shape.Accordingly, each side of the ground plane 28 may measure between 20 mmand 100 mm, and in a preferred embodiment, 60 mm. However, those skilledin the art realize that other shapes and sizes of the ground plane 28may be implemented.

The electromagnetic field is radiated by a dielectric layer 30sandwiched between the ground plane 28 and the nonconductive pane 26.The dielectric layer has a radiating surface 29 opposite the groundplane 28 and abutting the nonconductive pane 26. In addition to theabutting the nonconductive pane 26, the radiating surface 29 may be anyexposed surface of the dielectric layer 30. Any surface of thedielectric layer 30 not abutting the ground plane 28 is exposed and mayradiate. In other words, any exposed surface may be the radiatingsurface 29, and the dielectric layer 30 may include multiple radiatingsurfaces 29. Exciting the dielectric layer 30 causes the dielectriclayer 30 to generate an electromagnetic field from the radiating surface29. In doing so, the dielectric layer 30 radiates independent of ametal-based patch radiation element or layer. It should be understoodthat other surfaces of the dielectric layer 30 may radiate in additionto the radiating surface 29. In other words, any exposed surface of thedielectric layer 30 may act as the radiating surface 29. For instance,the exposed surfaces of the dielectric layer 30 include any surface notabutting the ground plane 28.

The dielectric layer 30 radiates the electromagnetic field according tonumerous properties of the dielectric layer 30. One of those propertiesis a relative permittivity. The dielectric layer 30 has a relativepermittivity between 1 and 100, and in a preferred embodiment, therelative permittivity is 9.4. It should be understood that the relativepermittivity is uniform between the dielectric layer 30 and theradiating surface 29. On the other hand, those skilled in the artrealize that the relative permittivity may be non-uniform between thedielectric layer 30 and the radiating surface 29. Another property ofthe dielectric layer 30 that influences the radiation of theelectromagnetic field is a loss tangent. The dielectric layer 30 has aloss tangent between 0.001 and 0.3, and in a preferred embodiment, theloss tangent is 0.01. Additionally, the nonconductive pane 26 mayoperate in combination with the dielectric layer 30 to radiate theelectromagnetic field.

As shown in FIGS. 3E-3H, and 3K-3L, the dielectric layer 30 maygenerally define a rectangular shape, and preferably a square shape.Each side of the dielectric layer 30 measures about one-quarter of awavelength λ of the RF signal to be received by the antenna 20.Accordingly, each side of the dielectric layer 30 may measure, forinstance, between 20 mm and 100 mm depending on the wavelengths λ of theRF signals. The RF signals transmitted by SDARS providers typically havea frequency between 2.32 GHz to 2.345 GHz. These frequencies translateinto wavelengths λ from 128 to 129 mm. Therefore, each side of thedielectric layer 30 measures preferably about 25 to 35 mm.Alternatively, as shown in FIGS. 3A-3D, and 3I-3J, the dielectric layer30 may generally define a circular shape. However, those skilled in theart realize that there are alternative embodiments where the dielectriclayer 30 defines other shapes and sizes depending on the type andfrequency of the signal to be received and/or transmitted.

Referring again to FIGS. 2A-B and 4, the antenna 20 further includes afeeding probe 42 which is energized for electrically exciting thedielectric layer 30 such that the electromagnetic field radiates fromthe radiating surface 29 and achieves circular polarization radiation.The feeding probe 42 is embedded within the dielectric layer 30. Thefeeding probe may extend only partially into the dielectric layer 30 toembed the feeding probe 42 in the dielectric layer 30. Alternatively,the feeding probe 42 may extend completely to the surface of thedielectric layer 30 to embed the feeding probe 42 within the dielectriclayer 30. In addition, the feeding probe 42 may be embedded in thedielectric layer 30 transverse to the ground plane 28. Here, the feedingprobe 42 extends perpendicularly from the ground plane 28 toward thenonconductive pane 26. The feeding probe 42 also extends at leastpartially into the dielectric layer 30, and the feeding probe 42 may becompletely surrounded by the dielectric layer 30. Although the groundplane 28 is electrically isolated from the feeding probe 42, the groundplane 28 provides a reference ground for the feeding probe 42. Thefeeding probe 42 is preferably formed of an electrically conductive wireand is generally parallel to the vertical axis 44 running through acenter of the dielectric layer 30. It is preferred that the feedingprobe 42 is spaced from the vertical axis 44 on the ground plane 28.

In a particularly preferred embodiment of the subject invention, theantenna 20 only consists essentially of the ground plane 28, thedielectric layer 30, and the feeding probe 42. In other words, theantenna 20 of this embodiment does not include a metal radiatingelement. As previously described, the dielectric layer 30 is disposed onthe ground plane 28 and has the radiating surface 29 directly abuttingthe nonconductive pane 26. In this particular embodiment, air is notconsidered to be the dielectric layer 30. The feeding probe 42 isembedded in the dielectric layer 30 for electrically exciting thedielectric layer 30 such that the electromagnetic field radiates fromthe radiating surface 29 and achieves circular polarization radiation.The antenna 20 in this embodiment may still be used with other antennacomponents, such as a radome, which is known to those skilled in the artas a protective covering of the antenna 20. In addition, the antenna 20of this embodiment may include multiple ground planes 28, a singledielectric layer 30 having multiple radiating surfaces 29, multipledielectric layers 30 having multiple radiating surfaces 29, or multiplefeed lines 42.

In another embodiment, referring to FIG. 5, those skilled in the artrealize that a passive element may be used in addition to the feedingprobe 42 for particular applications, including beam steering. Forinstance, the passive element may be an adhesive strip 31 attached to avertical surface of the dielectric layer 30. The adhesive strip 31excites the dielectric layer 30 to radiate the electromagnetic fieldfrom the radiating surface 29. Preferably, the adhesive strip 31 isformed from a metallic material, such as copper. Those skilled in theart realize that the adhesive strip 31 may be formed of other metals orcombinations of metals.

In another alternative embodiment, as shown in FIG. 13, at least part ofthe nonconductive pane 26 may be the dielectric layer 30 as disclosedsuch that the nonconductive pane 26 itself radiates, allowing theantenna 20 to be embedded within the nonconductive pane 26. In thisembodiment, the ground plane 28 abuts the nonconductive pane 26 and thefeeding probe 42 extends into and excites the nonconductive pane 26 togenerate the electromagnetic field. In order to prevent the entirenonconductive pane 26 from radiating and to overcome wave attenuation, aportion 50 of the nonconductive pane 26 may protrude outwardly and beexcited to produce the electromagnetic field. Allowing the entirenonconductive pane 26 to radiate will cause wave attenuation. It is tobe understood that there may be other ways to produce theelectromagnetic field. Those skilled in the art realize that the size ofthe portion 50 of the nonconductive pane 26 that protrudes variesdepending on the desired frequency. It is to be understood that thenonconductive pane 26 may be any window 22 in the vehicle 24, andpreferably, the nonconductive pane 26 is the rear window. In thisembodiment, the feeding probe 42 is embedded in the protruding portion50 of the nonconductive pane 26 such that the nonconductive pane 26radiates the electromagnetic field.

FIG. 5 is a schematic view of the feeding probe 42 embedded in thedielectric layer 30 offset from the center of the dielectric layer 30.The exact location of the feeding probe 42 relative to the ground plane28 and the dielectric layer 30, as well as the length of the feedingprobe 42, depend on both impedance and polarization characteristics ofthe specific antenna 20 design for a given application. For instance,under certain circumstances, it may be preferred that the length of thefeeding probe 42 extend to the radiating surface 29 opposite the groundplane 28. Those skilled in the art realize that other locations andlengths of the feeding probe 42 may be implemented to excite thedielectric layer 30 and generate an electromagnetic field.

Referring back to FIGS. 2 and 3A-3L, the dielectric layer 30 defines atleast one perturbation feature 32. The perturbation feature 32 of thedielectric layer 30 disturbs the electromagnetic field at appropriatelocations to excite two orthogonal components of the RF signal withequal amplitude and in-phase quadrature. In other words, theperturbation feature 32 causes a “disturbance” in the electromagneticfield radiated by the dielectric layer 30. The perturbation feature 32may be embodied in various quantities, configurations, shapes, andpositions and define at least one dimension corresponding to a desiredfrequency range and axial ratio of the RF signal being received and/ortransmitted. The desired frequency range is between 2.32 GHz and 2.345GHz, and preferably 2.338 GHz, which corresponds to a center frequencyused by XM® Satellite Radio.

Referring to FIG. 3L, the dielectric layer 30 may have a singleperturbation feature 32. However, typically, as shown in FIGS. 3A-3K,the dielectric layer 30 defines a pair of perturbation features 32. Eachperturbation feature 32 of the pair is preferably defined on thedielectric layer 30 opposite one another. However, each perturbationfeature 32 may be defined at locations not opposite to one another, aswell. Furthermore, those skilled in the art realize that the dielectriclayer 30 may define more than two perturbation features 32.

Referring to FIGS. 3A, 3C, 3F, and 3G, the perturbation feature 32 ofthe dielectric layer 30 may be implemented as a notch 34, preferablydefined inward from the periphery towards the center. Of course, thenotch 34 need not be defined towards a precise center of the dielectriclayer 30, but simply inward from the periphery. The perturbation feature32 of the dielectric layer 30 may also be implemented as a tab 36projecting outward from the periphery away from the center, as shown inFIGS. 3B, 3D, and 3H. Likewise, the tab 36 need not project outward froma precise center of the dielectric layer 30. Also, as shown in FIGS.3I-3L, the perturbation feature 32 may be defined as an aperture 38fully bounded within the dielectric layer 30. Those skilled in the artrealize that one perturbation feature 32 on the dielectric layer 30 maydefine the notch 34, while another perturbation feature 32 on thedielectric layer 30 may project the tab 36. Furthermore, those skilledin the art realize that other configurations for the perturbationfeatures 32 other than the notches 34, tabs 36, and apertures 38described above may be implemented.

Referring to FIGS. 3A, 3B, and 3I, the perturbation feature 32 maydefine a triangular shape, regardless of the configuration (notch 34,tab 36, void, or otherwise). As shown in FIGS. 3C, 3D, 3F, 3G, 3H, 3J,3K, and 3L, the perturbation feature 32 may also define a rectangularshape. Referring to FIG. 3E, the perturbation feature 32 may beimplemented as a truncation of a corner of a rectangular-shapeddielectric layer 30. Here, the perturbation features 32 are defined inopposing corners of the dielectric layer 30, and the perturbationfeatures 32 are “cut-outs” of the opposing corners. In other words, thedielectric layer 30 has a rectangular configuration with opposingcorners and the perturbation feature 32 is further defined as a pair oftruncations defined at the opposite corners. The perturbation features32 provide the dielectric layer 30 with circular polarization to receivethe circularly polarized RF signal from the satellite. Those skilled inthe art realize that other techniques of generating circularpolarization may be implemented. Moreover, those skilled in the artrealize that there are other suitable shapes for the perturbationfeatures 32.

Referring to FIGS. 3A through 3L, a lateral axis 40 may be definedthrough a midpoint of the perturbation feature 32. It is preferred thateach dielectric layer 30 is generally symmetrical about the lateral axis40. This symmetry assists in providing a preferred axial ratio of about0 dB. However, those skilled in the art realize that the antenna 20 maybe implemented without the dielectric layer 30 being symmetrical aboutthe lateral axis 40, particularly when a different axial ratio isdesired.

Returning to FIG. 4, the antenna 20 may further include a cover 46affixed to the nonconductive pane 26 to enclose the ground plane 28, thedielectric layer 30, and the feeding probe 42. The cover 46 protects theantenna 20 from dust, dirt, contaminants, accidental breakage, etc., aswell as providing the antenna 20 with a more aesthetic appearance.Additionally, an amplifier 48 may be disposed inside the cover 46. Inone embodiment, the amplifier 48 may be integrated into the ground plane28. Furthermore, the ground plane 28 may be used to ground the amplifier48. The amplifier 48 is electrically connected to the feeding probe 42to amplify the RF signal received by the antenna 20. The amplifier 48 ispreferably a low-noise amplifier (LNA) such as those well known to thoseskilled in the art.

The subject invention further includes a method of generating anelectromagnetic field to achieve circular polarization radiation.Operationally, the method includes exciting the dielectric layer 30 ofthe antenna 20 such that the dielectric layer 30 generates the radiationpattern in the electromagnetic field. The method may further use thefeeding probe 42 embedded in the dielectric layer 30. Here, the methodincludes energizing the feeding probe 42 to excite the dielectric layer30. Finally, the method includes defining at least one of theperturbation features 32 in the dielectric layer 30 that corresponds toa desired frequency range and axial ratio of the RF signal.

When radiating, the antenna 20 is subject to a return loss depending onthe frequency of the RF signal. FIG. 6 illustrates the magnitude of theS₁₁ parameter of the antenna 20 when the antenna 20 is operating withinthe desired frequency range. From this figure, the return loss isdetermined to be about 14 dB at the center frequency of the desiredfrequency range, and the desired frequency range provides a widerbandwidth of return loss values below 10 dB than typical patch-typeantennas. Similarly, the antenna input impedance is shown in FIG. 7 tobe a function of the frequency of the RF signal. FIGS. 8 and 9illustrate the frequency response, axial ratio and gain of the antenna20 covering the desired frequency range respectively. Referring to FIG.8, the optimal axial ratio occurs when the antenna 20 operates at thecenter frequency in the desired frequency range. Likewise, as shown inFIG. 9, the maximum desired gain occurs when the antenna 20 operates atthe center frequency in the desired frequency range. FIGS. 10 and 11illustrate a gain pattern of the antenna 20 at the desired frequencyrange of operation (in our case 2.338 GHz). In FIG. 10, the gain ismeasured in an XZ-plane of the antenna 20, and in FIG. 11 the gain ismeasured in a YZ-plane, which is perpendicular to the XZ-plane. Finally,FIG. 12 illustrates an axial ratio pattern of the antenna 20 operatingin the desired frequency range measured in the XZ-plane and theYZ-plane.

As set forth above, electrically exciting the dielectric layer 30 withthe feeding probe 42 generates an electromagnetic field that radiatesfrom the radiating surface 29 and achieves circular polarizationradiation. Accordingly, this provides the antenna 20 of the subjectinvention with better gain performance at 20 to 30 degree elevationangles. The antenna 20 of the subject invention achieves circularpolarization radiation and maintains or improves the performance whencompared to patch-type antennas, including increased bandwidth,increased efficiency, decreased size, decreased sensitivity, andminimized surface wave radiation.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. The invention may bepracticed otherwise than as specifically described within the scope ofthe appended claims.

1. An antenna for radiating an electromagnetic field, said antennacomprising: a ground plane; a dielectric layer disposed on said groundplane and having a radiating surface for radiating the electromagneticfield and at least one vertical surface generally perpendicular to saidradiating surface; a feeding probe embedded in said dielectric layer forelectrically exciting said dielectric layer such that theelectromagnetic field radiates from said radiating surfaces; saiddielectric layer further defining at least one perturbation feature fordisturbing the electromagnetic field and achieving circular polarizationradiation; and at least one passive element formed of a conductivematerial disposed adjacent said at least one vertical radiating surfaceand apart from said at least one perturbation feature.
 2. An antenna asset forth in claim 1 wherein said radiating surface is opposite andspaced from said ground plane.
 3. An antenna as set forth in claim 1wherein said feeding probe extends only partially into said dielectriclayer to embed said feeding probe in said dielectric layer.
 4. Anantenna as set forth in claim 1 wherein said feeding probe is embeddedin said dielectric layer transverse to said ground plane.
 5. An antennaas set forth in claim 1 wherein said at least one perturbation featuredefines at least one dimension corresponding to a desired frequencyrange and axial ratio of a radio frequency (RF) signal.
 6. An antenna asset forth in claim 1 wherein said dielectric layer includes a peripheryand a center and wherein said at least one perturbation feature isfurther defined as a notch defined inward from said periphery towardssaid center.
 7. An antenna as set forth in claim 1 wherein saiddielectric layer includes a periphery and a center and wherein said atleast one perturbation feature is further defined as a tab projectingoutward from said periphery away from said center.
 8. An antenna as setforth in claim 1 wherein said at least one perturbation feature isfurther defined as an aperture fully bounded within said dielectriclayer.
 9. An antenna as set forth in claim 1 further comprising alateral axis defined through a center of said dielectric layer andthrough a midpoint of said at least one perturbation feature and whereinsaid dielectric layer is generally symmetrical about said lateral axis.10. An antenna as set forth in claim 1 further comprising a verticalaxis defined through a center of said dielectric layer and perpendicularto said ground plane and wherein said feeding probe extends from saidground plane parallel to and spaced from said vertical axis.
 11. Anantenna as set forth in claim 1 further comprising an amplifierelectrically connected to said feeding probe for amplifying a signalreceived by said antenna.
 12. An antenna as set forth in claim 1 whereinsaid dielectric layer has a relative permittivity between 1 and
 100. 13.An antenna as set forth in claim 12 wherein said relative permittivityis uniform between said dielectric layer and said radiating surface. 14.An antenna as set forth in claim 12 wherein said relative permittivityis non-uniform between said dielectric layer and said radiating surface.15. An antenna as set forth in claim 1 wherein said dielectric layer hasa loss tangent between 0.001 and 0.03.
 16. An antenna as set forth inclaim 1 wherein said dielectric layer and said ground plane have aplurality of sides measuring between 20 mm and 100 mm.
 17. An antenna asset forth in claim 1 wherein said dielectric layer is further defined asa nonconductive pane to radiate the electromagnetic field.
 18. Anantenna as set forth in claim 17 wherein said nonconductive pane isfurther defined as automotive glass.
 19. An antenna as set forth inclaim 1 wherein said at least one passive element is in contact withsaid at least one vertical surface.
 20. An antenna as set forth in claim1 wherein said at least one passive element is further defined as astrip of metal running between said ground plane and said radiatingsurface.
 21. A window having an integrated antenna for radiating anelectromagnetic field, said window comprising: a nonconductive pane; aground plane spaced from and disposed substantially parallel to saidnonconductive pane; a dielectric layer sandwiched between said groundplane and said nonconductive pane; said dielectric layer having aradiating surface for radiating the electromagnetic field and at leastone vertical surface generally perpendicular to said radiating surface;a feeding probe embedded in said dielectric layer said dielectric layerfurther defining at least one perturbation feature for disturbing theelectromagnetic field and achieving circular polarization radiation; andat least one passive element formed of a conductive material disposedadjacent said at least one vertical surface and apart from said at leastone perturbation feature.
 22. A window as set forth in claim 21 whereinsaid radiating surface abuts said nonconductive pane.
 23. A window asset forth in claim 21 wherein said feeding probe extends only partiallyinto said dielectric layer to embed said feeding probe in saiddielectric layer.
 24. A window as set forth in claim 21 wherein saidfeeding probe is embedded in said dielectric layer transverse to saidground plane.
 25. A window as set forth in claim 21 wherein said atleast one perturbation feature defines at least one dimensioncorresponding to a desired frequency range and axial ratio of a radiofrequency (RF) signal.
 26. A window as set forth in claim 21 whereinsaid dielectric layer includes a periphery and a center and wherein saidat least one perturbation feature is further defined as at least one ofa notch defined inward from said periphery towards said center and a tabextending outward from said periphery away from said center.
 27. Awindow as set forth in claim 21 wherein said dielectric layer has arectangular configuration with opposing corners and wherein said atleast one perturbation feature is further defined as a pair oftruncations defined in said opposing corners.
 28. A window as set forthin claim 21 wherein said at least one perturbation feature is furtherdefined as an aperture fully bounded within said dielectric layer.
 29. Awindow as set forth in claim 21 further comprising a lateral axisdefined through a center of said dielectric layer and through a midpointof said at least one perturbation feature and wherein said dielectriclayer is generally symmetrical about said lateral axis.
 30. A window asset forth in claim 21 further comprising a vertical axis defined througha center of said dielectric layer and wherein said feeding probe extendsfrom said ground plane parallel to and spaced from said vertical axis.31. A window as set forth in claim 21 further comprising an amplifierelectrically connected to said feeding probe for amplifying a signalreceived by said antenna.
 32. A window as set forth in claim 21 whereinsaid dielectric layer has a relative permittivity between 1 and
 100. 33.An antenna as set forth in claim 32 wherein said relative permittivityis uniform between said dielectric layer and said radiating surface. 34.An antenna as set forth in claim 32 wherein said relative permittivityis non-uniform between said dielectric layer and said radiating surface.35. A window as set forth in claim 21 wherein said dielectric layer hasa loss tangent between 0.001 and 0.03.
 36. A window as set forth inclaim 21 wherein said dielectric layer and said ground plane have aplurality of sides measuring between 20 mm and 100 mm.
 37. A window asset forth in claim 21 wherein said nonconductive pane is further definedas automotive glass.
 38. A window having an integrated antenna forradiating an electromagnetic field, said window comprising: a pane ofautomotive glass defining a radiating portion of automotive glassprotruding from said pane of automotive glass for radiating theelectromagnetic field; a ground plane disposed on said pane ofautomotive glass; and a feeding probe embedded in said portion of saidpane of automotive glass for exciting said pane of automotive glass suchthat said pane of automotive glass radiates the electromagnetic field.